An incompetent cervix, also called a cervical insufficiency, occurs when weak cervical tissue causes or contributes to premature birth or the loss of an otherwise healthy pregnancy.
Before pregnancy, your cervix — the lower part of the uterus that opens to the vagina — is normally closed and firm. As pregnancy progresses and you prepare to give birth, the cervix gradually softens, decreases in length (effaces) and opens (dilates). If you have an incompetent cervix, your cervix might begin to open too soon — causing you to give birth too early.
An incompetent cervix can be difficult to diagnose and treat. If your cervix begins to open early, or you have a history of cervical insufficiency, your doctor might recommend preventive medication during pregnancy, frequent ultrasounds or a procedure that closes the cervix with strong sutures (cervical cerclage).
If you have an incompetent cervix, you may not have any signs or symptoms during early pregnancy. Some women have mild discomfort or spotting over the course of several days or weeks starting between 14 and 20 weeks of pregnancy.
Be on the lookout for:
- A sensation of pelvic pressure
- A new backache
- Mild abdominal cramps
- A change in vaginal discharge
- Light vaginal bleeding
Many women don't have a known risk factor. Risk factors for cervical insufficiency include:
- Cervical trauma. Some surgical procedures used to treat cervical abnormalities associated with an abnormal Pap smear can result in cervical insufficiency. Other surgical procedures such as a D&C could also be associated with cervical insufficiency. Rarely, a cervical tear during a previous labor and delivery could be associated with an incompetent cervix.
- Race. Black women seem to have a higher risk of developing cervical insufficiency. It isn't clear why.
- Congenital conditions. Uterine abnormalities and genetic disorders affecting a fibrous type of protein that makes up your body's connective tissues (collagen) might cause an incompetent cervix. Exposure to diethylstilbestrol (DES), a synthetic form of the hormone estrogen, before birth also has been linked to cervical insufficiency.
An incompetent cervix poses risks for your pregnancy — particularly during the second trimester — including:
- Premature birth
- Pregnancy loss
You can't prevent an incompetent cervix — but there's much you can do to promote a healthy, full-term pregnancy. For example:
- Seek regular prenatal care. Prenatal visits can help your doctor monitor your health and your baby's health. Mention any signs or symptoms that concern you, even if they seem silly or unimportant.
- Eat a healthy diet. During pregnancy, you'll need more folic acid, calcium, iron and other essential nutrients. A daily prenatal vitamin — ideally starting a few months before conception — can help fill any dietary gaps.
- Gain weight wisely. Gaining the right amount of weight can support your baby's health. A weight gain of 25 to 35 pounds (about 11 to 16 kilograms) is often recommended for women who have a healthy weight before pregnancy.
- Avoid risky substances. If you smoke, quit. Alcohol and illegal drugs are off-limits, too. In addition, get your doctor's OK before taking any medications or supplements — even those available over-the-counter.
If you've had an incompetent cervix during one pregnacy, you're at risk of premature birth or pregnancy loss in later pregnancies. If you're considering getting pregnant again, talk with your doctor to understand the risks and what you can do to promote a healthy pregnancy.
July 25, 2019
- Berghella V, et al. Cervical insufficiency. https://www.uptodate.com/contents/search. Accessed Feb. 8, 2018.
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- Tanner LD, et al. Maternal race/ethnicity as a risk factor for cervical insufficiency. European Journal of Obstetrics & Gynecology and Reproductive Biology. 2018;221:156.
- Boelig RC, et al. Current options for mechanical prevention of preterm birth. Seminars in Perinatology. 2017;41:452.
- American College of Obstetricians and Gynecologists (ACOG) Committee on Practice Bulletins — Obstetrics. ACOG Practice Bulletin No. 142: Cerclage for the management of cervical insufficiency. Obstetrics & Gynecology. 2014;123:372.
- What can I do to promote a healthy pregnancy? National Institute of Child Health and Human Development. https://www.nichd.nih.gov/health/topics/preconceptioncare/conditioninfo/healthy-pregnancy. Accessed Feb. 1, 2018.